JDOM XML Parsing: not entering for loop - xml-parsing

Question

I want to parse and print XML tags using jdom2 (not w3c/xml.sax)
the root element is getting printed and the debug till before for loop is also there, but after that, there's blank, no syntax error, am I missing something in the for loop?
this is what my main looks like in the message reader class
public class XMLReaderDOM {
public static void main(String[] args) {
System.out.println("Starting out now");
try {
SAXBuilder builder = new SAXBuilder();
File xmlFile = new File("file.xml");
Document doc = (Document) builder.build(xmlFile);
Element root = doc.getRootElement();
System.out.println("Document built");
List < Element > listGrpHdr = root.getChildren("GrpHdr");
List < GrpHdr > grphdrList = new ArrayList <>();
System.out.println("root element:" + doc.getRootElement().getName());
System.out.println("Right before for");
for (Element grphdrElement: listGrpHdr){
GrpHdr grphdr = new GrpHdr();
System.out.println("before getting our elements");
grphdr.setGrp_id(grphdrElement.getChildText("grp_id"));
grphdr.setCreationDateTime(grphdrElement.getChildText("creationDateTime"));
grphdr.setMessageType(grphdrElement.getChildText("messageType"));
grphdr.setGrp_hdr_xml(grphdrElement.getChildText("grp_hdr_xml"));
grphdrList.add(grphdr);
}
grphdrList.forEach(grphdr->{
System.out.println(grphdr.toString());
});
} catch (Exception e) {
e.printStackTrace();
}
}
}